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AJvYcCUFSP5u/I6vuPGVKzlNNTU1N2RomY5ANQirgydS+HlD8f1pWRP1NxZ3KbJoQ/LgDa3Ho2iiuNQl/ujdF6Yl3uu/nmnJHnszX4n6kboUxzBiuVXn/DivL4k/47mQozqbesjlcSJ5ORvZzA== X-Gm-Message-State: AOJu0YxqpQnh4AL1O+HuHHEp3acVztKhipQAPVR/sBk7CGgUw4BlsUa1 C/5NSK4z8t6trYuTEXMMVrKS7Cj9ilZqft8y8Zjg+tlRRhRK+EVcVcQQfA== X-Google-Smtp-Source: AGHT+IFHu08PYRN6jEQnolZOFmTs5J85KJFSA1Kh6G/URpnfRtUbR/dKyK+cRFq8LA+pJ3vZBZJ8UA== X-Received: by 2002:a05:6a21:1f20:b0:1b0:14ee:3b1b with SMTP id adf61e73a8af0-1b26f23d544mr9878532637.38.1717473767800; Mon, 03 Jun 2024 21:02:47 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1f6574f6353sm48929415ad.260.2024.06.03.21.02.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Jun 2024 21:02:47 -0700 (PDT) Sender: Guenter Roeck From: Guenter Roeck To: linux-hwmon@vger.kernel.org Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Krzysztof Kozlowski , Wolfram Sang , =?utf-8?q?Ren=C3=A9_Rebe?= , =?utf-8?q?Thomas_Wei=C3=9Fs?= =?utf-8?q?chuh?= , Armin Wolf , Stephen Horvath , Guenter Roeck Subject: [PATCH v4 4/6] hwmon: (spd5118) Add support for reading SPD data Date: Mon, 3 Jun 2024 21:02:35 -0700 Message-Id: <20240604040237.1064024-5-linux@roeck-us.net> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240604040237.1064024-1-linux@roeck-us.net> References: <20240604040237.1064024-1-linux@roeck-us.net> Precedence: bulk X-Mailing-List: linux-hwmon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add support for reading SPD NVMEM data from SPD5118 (Jedec JESD300) compliant memory modules. NVMEM write operation is not supported. NVMEM support is optional. If CONFIG_NVMEM is disabled, the driver will still instantiate but not provide NVMEM attribute files. Signed-off-by: Guenter Roeck Tested-by: Armin Wolf --- v4: Use NVMEM_DEVID_NONE instead of NVMEM_DEVID_AUTO Ignore nvmem registration failure if nvmem support is disabled v3: New patch Documentation/hwmon/spd5118.rst | 8 ++ drivers/hwmon/spd5118.c | 147 +++++++++++++++++++++++++++++++- 2 files changed, 151 insertions(+), 4 deletions(-) diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst index a15d75aa2066..ef7338f46575 100644 --- a/Documentation/hwmon/spd5118.rst +++ b/Documentation/hwmon/spd5118.rst @@ -53,3 +53,11 @@ temp1_crit_alarm Temperature critical alarm Alarm attributes are sticky until read and will be cleared afterwards unless the alarm condition still applies. + + +SPD (Serial Presence Detect) support +------------------------------------ + +The driver also supports reading the SPD NVRAM on SPD5118 compatible chips. +SPD data is available from the 'eeprom' binary attribute file attached to the +chip's I2C device. diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c index d55c073ff5fd..5cb5e52c0a38 100644 --- a/drivers/hwmon/spd5118.c +++ b/drivers/hwmon/spd5118.c @@ -20,6 +20,8 @@ #include #include #include +#include +#include #include #include #include @@ -53,12 +55,31 @@ static const unsigned short normal_i2c[] = { #define SPD5118_TS_DISABLE BIT(0) /* temperature sensor disable */ +#define SPD5118_LEGACY_MODE_ADDR BIT(3) +#define SPD5118_LEGACY_PAGE_MASK GENMASK(2, 0) +#define SPD5118_LEGACY_MODE_MASK (SPD5118_LEGACY_MODE_ADDR | SPD5118_LEGACY_PAGE_MASK) + + +#define SPD5118_NUM_PAGES 8 +#define SPD5118_PAGE_SIZE 128 +#define SPD5118_PAGE_SHIFT 7 +#define SPD5118_PAGE_MASK GENMASK(6, 0) +#define SPD5118_EEPROM_BASE 0x80 +#define SPD5118_EEPROM_SIZE (SPD5118_PAGE_SIZE * SPD5118_NUM_PAGES) + /* Temperature unit in millicelsius */ #define SPD5118_TEMP_UNIT (MILLIDEGREE_PER_DEGREE / 4) /* Representable temperature range in millicelsius */ #define SPD5118_TEMP_RANGE_MIN -256000 #define SPD5118_TEMP_RANGE_MAX 255750 +struct spd5118_data { + struct regmap *regmap; + struct mutex nvmem_lock; +}; + +/* hwmon */ + static int spd5118_temp_from_reg(u16 reg) { int temp = sign_extend32(reg >> 2, 10); @@ -360,9 +381,111 @@ static const struct hwmon_chip_info spd5118_chip_info = { .info = spd5118_info, }; +/* nvmem */ + +static int spd5118_nvmem_set_page(struct regmap *regmap, int page) +{ + unsigned int old_page; + int err; + + err = regmap_read(regmap, SPD5118_REG_I2C_LEGACY_MODE, &old_page); + if (err) + return err; + + if (page != (old_page & SPD5118_LEGACY_MODE_MASK)) { + /* Update page and explicitly select 1-byte addressing */ + err = regmap_update_bits(regmap, SPD5118_REG_I2C_LEGACY_MODE, + SPD5118_LEGACY_MODE_MASK, page); + if (err) + return err; + + /* Selected new NVMEM page, drop cached data */ + regcache_drop_region(regmap, SPD5118_EEPROM_BASE, 0xff); + } + + return 0; +} + +static ssize_t spd5118_nvmem_read_page(struct regmap *regmap, char *buf, + unsigned int offset, size_t count) +{ + int err; + + err = spd5118_nvmem_set_page(regmap, offset >> SPD5118_PAGE_SHIFT); + if (err) + return err; + + offset &= SPD5118_PAGE_MASK; + + /* Can't cross page boundaries */ + if (offset + count > SPD5118_PAGE_SIZE) + count = SPD5118_PAGE_SIZE - offset; + + err = regmap_bulk_read(regmap, SPD5118_EEPROM_BASE + offset, buf, count); + if (err) + return err; + + return count; +} + +static int spd5118_nvmem_read(void *priv, unsigned int off, void *val, size_t count) +{ + struct spd5118_data *data = priv; + char *buf = val; + int ret; + + if (unlikely(!count)) + return count; + + if (off + count > SPD5118_EEPROM_SIZE) + return -EINVAL; + + mutex_lock(&data->nvmem_lock); + + while (count) { + ret = spd5118_nvmem_read_page(data->regmap, buf, off, count); + if (ret < 0) { + mutex_unlock(&data->nvmem_lock); + return ret; + } + buf += ret; + off += ret; + count -= ret; + } + mutex_unlock(&data->nvmem_lock); + return 0; +} + +static int spd5118_nvmem_init(struct device *dev, struct spd5118_data *data) +{ + struct nvmem_config nvmem_config = { + .type = NVMEM_TYPE_EEPROM, + .name = dev_name(dev), + .id = NVMEM_DEVID_NONE, + .dev = dev, + .base_dev = dev, + .read_only = true, + .root_only = false, + .owner = THIS_MODULE, + .compat = true, + .reg_read = spd5118_nvmem_read, + .priv = data, + .stride = 1, + .word_size = 1, + .size = SPD5118_EEPROM_SIZE, + }; + struct nvmem_device *nvmem; + + nvmem = devm_nvmem_register(dev, &nvmem_config); + return PTR_ERR_OR_ZERO(nvmem); +} + +/* regmap */ + static bool spd5118_writeable_reg(struct device *dev, unsigned int reg) { switch (reg) { + case SPD5118_REG_I2C_LEGACY_MODE: case SPD5118_REG_TEMP_CLR: case SPD5118_REG_TEMP_CONFIG: case SPD5118_REG_TEMP_MAX: @@ -396,7 +519,7 @@ static bool spd5118_volatile_reg(struct device *dev, unsigned int reg) static const struct regmap_config spd5118_regmap_config = { .reg_bits = 8, .val_bits = 8, - .max_register = SPD5118_REG_TEMP_STATUS, + .max_register = 0xff, .writeable_reg = spd5118_writeable_reg, .volatile_reg = spd5118_volatile_reg, .cache_type = REGCACHE_MAPLE, @@ -406,10 +529,15 @@ static int spd5118_probe(struct i2c_client *client) { struct device *dev = &client->dev; unsigned int regval, revision, vendor, bank; + struct spd5118_data *data; struct device *hwmon_dev; struct regmap *regmap; int err; + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + regmap = devm_regmap_init_i2c(client, &spd5118_regmap_config); if (IS_ERR(regmap)) return dev_err_probe(dev, PTR_ERR(regmap), "regmap init failed\n"); @@ -433,7 +561,16 @@ static int spd5118_probe(struct i2c_client *client) if (!spd5118_vendor_valid(bank, vendor)) return -ENODEV; - dev_set_drvdata(dev, regmap); + data->regmap = regmap; + mutex_init(&data->nvmem_lock); + dev_set_drvdata(dev, data); + + err = spd5118_nvmem_init(dev, data); + /* Ignore if NVMEM support is disabled */ + if (err && err != -EOPNOTSUPP) { + dev_err_probe(dev, err, "failed to register nvmem\n"); + return err; + } hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118", regmap, &spd5118_chip_info, @@ -454,7 +591,8 @@ static int spd5118_probe(struct i2c_client *client) static int spd5118_suspend(struct device *dev) { - struct regmap *regmap = dev_get_drvdata(dev); + struct spd5118_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; u32 regval; int err; @@ -479,7 +617,8 @@ static int spd5118_suspend(struct device *dev) static int spd5118_resume(struct device *dev) { - struct regmap *regmap = dev_get_drvdata(dev); + struct spd5118_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; regcache_cache_only(regmap, false); return regcache_sync(regmap);